Experiments aimed at the detection of breast tissue specific gene expression have led to the isolation of a mRNA which encodes a new member of the chemokine family of cytokines. This protein, mammary associated chemokine ("MACK"), shares biochemical characteristics with other Beta-chemokines and also has been detected in the soluble fraction of human milk. Antisera to MACK have been produced against synthetic peptides which correspond to regions of the deduced protein. Using the antisera, a qualitative Western blot protocol has been used to detect MACK in human serum. At high incidence, patients with breast cancer have MACK in their serum, whereas normal controls have no detectable circulating protein. In order to create a more sensitive and quantitative assay, the MACK gene sequence has been inserted into a baculovirus expression system and the transfected Sf9 cells produce high levels of the protein. The goals of Phase I are to purify the recombinant protein, produce monoclonal antibodies, and to develop a quantitative ELISA for the measurement of the protein in serum. To be studied are sera from patients with malignancy, including adenocarcinomas of various histotypes, leukemias-lymphomas and sarcomas. We will also examine specimens from patients with infectious diseases, autoimmune disorders and age- and sex- matched individuals. Overall, we will determine the clinical utility and efficacy of the test in the monitoring and detection of human breast cancer. PROPOSED COMMERCIAL APPLICATIONS: Effective new diagnostic tests for breast cancer will play a pivotal role in future approaches to screen and monitor the disease.